Project Summary The goal of the proposed study is to characterize patterns of disability by nativity and generational status and the influence of social networks over time among Mexican Americans. The role of nativity and generational status in the development of disability is central to this proposal. Data from the Hispanic Established Population for Epidemiological Studies of the Elderly (HEPESE) a large, multistage probability sample of Mexican Americans 65 and older who reside in the southwestern states of Texas, California, New Mexico, Arizona, and Colorado will be used. The first wave of the study (1993) surveyed 3,050 individuals. This cohort was re-contacted approximately every two years between 1995 and 2011. Research on disability has largely focused on non- Hispanic Black-White differences controlling for demographic and socioeconomic variables, and the role of nativity and generational status in the process of disability has received relatively little attention. In addition, in this study we aim to evaluate if changes in disability over time may be due to the erosion of social networks that provide health- enhancing support to individuals. This aim will be assessed by evaluating if any observed nativity-disability association changes after the inclusion of social network measures among foreign and native born Mexican Americans using HEPESE data. The physical functioning sections in HEPESE provide self-reported data on functional limitations caused by long-term physical, mental, and emotional problems or illness. These sections will be used to assess an individual's level of disability. Hierarchical generalized linear models will be used to calculate the disability trajectories while accounting for within-individual and between-individual variability over repeated assessments, and for cross-level interactions between time and each of the covariates. This project will examine approximately 20- year estimates of disability for foreign and native born Mexicans and how disability rates for each group change over time, while meaningfully improving our knowledge of mediating factors, specifically generational status and social networks. This evidence can be used to design more effective public health policy and intervention approaches that recognize the important role of nativity, generational status and social network factors for a large segment of the US population facing significant disability burdens.